<jats:p> <jats:bold>Four <jats:italic>pap</jats:italic> genes (<jats:italic>papA</jats:italic>, <jats:italic>papB</jats:italic>, <jats:italic>papC</jats:italic>, <jats:italic>papM</jats:italic> ) were found by sequencing near to <jats:italic>snbA</jats:italic>, a <jats:italic>Streptomyces pristinaespiralis</jats:italic> gene which was previously shown to encode one of the pristinamycin I (PI) synthetases. Analysis of the homologies observed from the deduced amino acid sequences suggested that these four genes could be involved in the biosynthesis of the PI precursor 4‐dimethylamino‐<jats:sc>l</jats:sc>‐phenylalanine (DMPAPA). This was first verified when disruption of <jats:italic>papA</jats:italic> in <jats:italic>S. pristinaespiralis</jats:italic> led to a PI<jats:sup>−</jats:sup> phenotype, which was reversed by the addition of DMPAPA into the culture medium. Further confirmation was obtained when <jats:italic>papM</jats:italic> was overexpressed in <jats:italic>Escherichia coli</jats:italic> and the corresponding protein purified to homogeneity. It catalysed the two successive <jats:italic>N</jats:italic>‐methylation steps of 4‐amino‐<jats:sc>l</jats:sc>‐phenylalanine leading to DMPAPA via 4‐methylamino‐<jats:sc>l</jats:sc>‐phenylalanine. These results allowed us to assign a function to each of the four <jats:italic>pap</jats:italic> genes and to propose a biosynthetic pathway for DMPAPA.</jats:bold>